Broad Fe-K lines from Seyfert galaxies Original Research Article

ASCA X-ray spectra of many Seyfert galaxies show a broad, skew, iron emission line consistent with emission from a relativistic disk around a black hole. The line is an important diagnostic with which to study the geometry and other properties of the accretion flow very close to the central black hole. It indicates the presence of a standard thin accretion disk within the inner few tens of gravitational radii in those objects. The general properties and observational results on the line are reviewed, together with details from two long observations of MCG-6-30-15.